Health Officials: H1n1 Vaccine Safe

Few Side Effects, But Results Are Still Preliminary

December 6, 2009|By Denise Grady The New York Times

An extensive review of adverse effects from the swine flu vaccine indicates that the vaccine is safe, with side effects no different from those of seasonal flu vaccines, health officials have reported.

Dr. Thomas R. Frieden, director of the Centers for Disease Control and Prevention, called the findings "very reassuring" at a news briefing on Friday. But he also noted that the results were still preliminary, because the vaccine for the H1N1 flu has been in widespread use for about only two months, since Oct. 5, when the first doses became available to the public. Rare problems or delayed effects might not show up until later, after many more people are vaccinated. The disease centers also posted a report on the vaccine's safety on its website.

The information comes from two monitoring networks. One is the Vaccine Adverse Event Reporting System, which receives reports about problems from doctors and other health workers, manufacturers and the public. Anyone can file a report, so there is no way of knowing if the problems are actually related to the vaccine until reports are investigated.

The second system is the Vaccine Safety Datalink, which has information on 438,376 people who were vaccinated for H1N1 in managed-care organizations.

According to the new report, "no substantial differences between H1N1 and seasonal influenza vaccines were noted in the proportion or types of serious adverse events reported."

Frieden said there was no sign that the swine flu vaccine could increase the risk of Guillain-Barre syndrome, a rare neuromuscular problem that was linked to a different swine flu vaccine used in 1976. Frieden said that the likelihood of an increased risk of the syndrome this time was "vanishingly remote," but that the disease centers would continue monitoring intensively for all adverse effects.

By Nov. 24, 3,783 adverse events had been reported after H1N1 vaccinations, of which 204 were considered serious, a category that includes death, life-threatening illness and significant disability. Most of the serious cases are still being reviewed. Nerve and muscle conditions, pneumonia, allergic reactions and gastrointestinal disorders are among the problems reported.

Dr. Claudia Vellozzi, deputy director of the immunization safety office at the disease centers, said scientists looked for commonalities and telltale patterns of illness among adverse events as a tip-off that they might be related to the vaccine. So far, Vellozzi said, no patterns have emerged.